1. Field of the Invention
The present invention relates to a sliding-type electric component, which are used for a potentiometer or the like of an automotive vehicle, and to a technology to enable reduction of conductive resistance in a conducting route and provision of highly reliable products.
2. Description of the Related Art
Hitherto, as shown in FIG. 15, a variable resistor having a sliding contact member including a slider 105 slidably provided along a guide rod 108 within a laterally elongated casing 100 having a slit 100a on its top plate, a resistance board 103 having a resistive element 102 patterned on the surface thereof below the slider 105, a sliding element 104 provided on the bottom of the slider 105 so as to slide with respect to the resistive element 102 during operation, an operating lever 105a formed on top of the slider 105 so as to project from the slit 100a, and a pair of coil springs 106, 107, being formed of shape memory alloy, provided at both ends of the guide rod 108 for clamping the slider 105 in a state of being abutted against stoppers 110, 110 is known.
In the variable resistor in this structure, reciprocal movement of the slider 105 along the guide rod 108 causes the sliding element 104 to slide while keeping in contact with the resistive element 102. However, since an extremity 104a of the sliding element 104 rubs the surface of the resistive element 102, a stable sliding movement of the sliding element 104 is achieved by, for smooth sliding movement, providing a grease trap 109 on one side of the resistance board 103, allowing the coil springs 106, 107, which deform into a predetermined shape at a predetermined temperature, to cause the extremity 104a of the sliding element 104 to pass through the grease trap 109 and get grease attached thereon, and supplying attached grease over the surface of the resistive element 102.
However, in the variable resistor in the construction shown in FIG. 15, there are problems in that supply of grease in the case where the variable resistor is inclined is liable to be unstable, and in that supply of grease may further be unstable in the case in which the variable resistor is subjected to repetitive vibrations in the inclined state. In addition, since the coil springs 106, 107 must be provided on both sides of the slider 105, and the coil springs are expensive, the cost of components tend to increase. Furthermore, although a metallic press member is employed as the sliding element 104 in the construction shown in FIG. 15, there are problems in that the metallic sliding element 104 is liable to generate noise when sliding with respect to the resistive element 102, and in that the surface of the resistive element 102 tends to be worn easily due to the repetitive sliding movement, and thus ground powder may easily be generated in the area around the sliding contact member.
In view of such circumstanced, one object of the invention is to provide a sliding-type electric component in which lubricant, such as grease, can definitely be contained, supply of lubricant can automatically be made, wear thereof at the contact point is reduced, generation of sliding noise is reduced, and possibility to grind a track of a conductive pattern with respect to which the sliding contact member slides and thus to generate ground powder is reduced, and to provide a sliding-type electric component and a sensor.
In order to solve the problem described above, a sliding-type electric component of the invention includes a contact element, and is characterized in that the contact element includes a bundle of carbon fibers formed by bundling a plurality of carbon fibers and lubricant contained among the plurality of carbon fibers of the bundle of carbon fibers, and at least part of the bundle of carbon fibers is capable of a sliding movement with respect to a track of a conductive pattern.
Lubricant is contained among the bundled carbon fibers of the bundle of the carbon fibers. The lubricant is automatically supplied to a sliding portion of the bundle of carbon fibers, which slides with respect to a separate member.
According to the invention, preferably, the bundle of carbon fibers is constructed in such a manner that each carbon fiber extends toward a contact point, which is formed on a part of the bundle of carbon fibers, and lubricant contained among the plurality of carbon fibers is held along the length of the carbon fibers so as to be supplied freely to the contact point.
Since the bundle of carbon fibers slide with respect to the track of the conductive pattern while supplying lubricant according to the invention, possibility to grind the track is reduced in comparison with a case in which the carbon fibers are simply slid, and thus the track is hardly ground, thereby slowing progress of wear of the track. Therefore, when the track is subjected to the repetitive reciprocating sliding movement, sliding characteristic of the contact element with respect to the track becomes stable, and thus withstanding long term of use.
The track of the conductive pattern applied herein may be any of a layer of resistive element, a layer of conductive element, a collector layer, and a metallic layer, and may be a lamination layer of the same.
In the sliding contact member according to the invention, an embracing member for partly surrounding the bundle of carbon fibers and supporting the bundle of carbon fibers is provided, and the carbon fibers constituting the bundle of carbon fibers are held in close contact with each other by the embracing member.
When the carbon fibers of the bundle of carbon fibers are held in close contact with each other, gaps among the carbon fibers may be reduced in the area held by the embracing member or the area not held by the embracing member. Therefore, lubricant can easily be contained in the gaps among the carbon fibers. Even when the lubricant is liquid such as lubricating oil, when the carbon fibers of the bundle of the carbon fibers are closely bundled, the lubricant can be held sufficiently by surface tension, and thus it can be held among the carbon fibers without problem even when the lubricant is grease or the like.
In order to solve the above-described problem, the sliding contact member according to the invention is characterized in that the embracing member for partly embracing and supporting the bundle of carbon fibers is provided, the carbon fibers constituting the bundle of carbon fibers are held in close contact with each other by the embracing member, and lubricant is contained internally of the embracing member.
Since the carbon fibers are held closely by the embracing member, the respective carbon fibers are held in close contact with each other, and lubricant is contained internally of the embracing member. Therefore, supply of lubricant can be held stably for a long time.
In order to solve the above-described problem, the present invention is characterized in that the embracing member is formed of metallic material formed so as to clamp at least part of the bundle of carbon fibers.
Since the bundle of carbon fibers is held so as to clamp by the metallic material, the carbon fibers can be held in further close contact.